Electrons and Quantum Mechanics - Oakland Schools

Discussion
Chemiluminescence is defined as the production or emission of light that accompanies a
chemical reaction. Light emission results from the conversion of chemical energy into
light energy due to changes in the composition of a chemiluminescent material.
The “flame test” colors observed when different metal salts are burned in a Bunsen
burner flame are examples of a type of chemiluminescence known as
pyroluminescence. The oxidation of luminol (3-aminophthalhydrazide) in this
demonstration is another well-known example of chemiluminescence. The lightproducing
chemical reactions of luminol were discovered by H. O. Albrecht in 1928.
Since that time numerous procedures have been developed to produce light using
luminol. Experiments have shown that the following “ingredients” are necessary for
luminol to exhibit chemiluminescence—a basic (alkaline) pH, an oxidizing agent, and a
catalyst. In this demonstration, the oxidizing agent is Clorox 2, which also maintains the
basic pH needed, and the catalyst is the iron(III) cation in potassium ferricyanide.
Oxidation of luminol and the resulting chemiluminscence occurs in the following
sequence of reactions:
1. Chlorox 2 acts as a base and converts luminol (structure I) into a dianion.
2. Chlorox 2 oxidizes the dianion form of luminol to aminophthalate ion (structure II),
which is produced in an excited electronic state (electrons not occupying their lowest
energy orbital).
3. The excited aminophthalate ion decays to a lower energy ground state and gives off
light in the process (structure III). The emitted light has a wavelength of 425 nm,
which is in the blue region of the visible spectrum.
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